Plaster board



E. WESTBERG PLASTER BOARD May 25 1926.

Filed Dec. 22, 1924 In ueni'ol" Edam/w! 9! flttorneys.

Patented May 25, 1926. I

UNITED STATES EDWARD WESTBERG, 033 LOS ANGELES, CALIFORNIA.

PLASTER BOARD.

Application filedDecember 22, 1924. Serial No. 757,396.

This invention relates, to plaster boards, and the object of the invention is to provide a plaster board embodying various improvements over such boards now in use. Briefly, these improvements include the covering of the board with a waterproof material, preferably paper, in the manner hereinafter specifically-described, and the forming of the outer surface of the paper into a plurality of depressions and projections. The particular construction and arrangement of these improvements will be apparent from the following description, taken in connection with the accompanying drawing. It should be understood, however, that while in such drawing I have illustrated one specific embodiment of my invention, the invention can be otherwise embodied within the scope of the appended claims, without departing from the spirit thereof.

Referring to the figures of the drawing,

Fig. 1 is a fragmentary view of a sheet of my improved plaster board;

Fig. 2 is a cross-sectional view thereof;

Fig. 3 is a fragmentary cross-sectional view, showing a modification of the invention.

As illustrated, my improved board comprises a plaster board composition 1, of a desired thickn ss, covered preferably on both sides the eof with paper coverings 2 and 3. Preferably both of such coverings are of waterproof material, as illustrated in the drawing, though obviously only the covering 2 need be waterproof, if desired.

The paper coverings can be of any desired form, though the outer and exposed surface thereof is preferably unsized. In Figs. 1 and 2 the outside or exposed surface of each covering 2 and 3 is unsized, and the inner surface, next to the board composition 1, is waterproof. In Fig. 3 both sides 4 and 5 of the paper covering are unsized and. contain a waterproof layer 6 there-between.

This latter form at present is believed to be preferable, for various reasons.

Another novel feature of my invention is the forming of the outer or plaster-receiving side 2 of my improved board with a plurality of identations 7 and projections 8. These indentations and projections are preferably formed in the arrangement shown in the drawing, whereby such surface of the board is given an undulating contour. It will be obvious that such a'surface will receive the plaster in a manner forming a more perfect bond to hold the plaster secured to the board.

It is believed that the several improvements and advantages of my invention will be clear without further description herein.

What I claim and desire to secure by Letters Patent is:

1. An improved plaster board comprising the combination of a plaster board composition having both sides thereof covered with paper, the surface of one of said sides of the board being formed with a plurality of projections thereon and indentations therein, said projections and indentations being spaced apart in staggered relation both longitudinally and transversely of the board whereby the surface of the board having the projections and indentations will be undulated both longitudinally and transversely of the board.

2. An improved plaster board comprising the combination of a plaster board composition having one side thereof covered with paper, the paper having a waterproof layer adjacent the composition, the other side of the board being formed with a plurality of knob-like projections spaced apart both longitudinally and transversely of the board and relatively staggered, and a plurality of indentations formed intermediate said knoblike projectionsand spaced therefrom.

EDWARD WESTBERG. 

